Art of pressure distillation



E. M.`CLARK.

ART 0Fv PRESSURE DISTILLATION.

APPLICATION F1LEn-APR.21.1919.

lmgm, m6111611 Mar. 22,1922,

2 SHEETS-SHEET 1.

E. M. CLARK.

ART 0F PRESSURE msTlLLATloN.

APPLICATION FILED lAIII. 21, 19H1.

Patented Mar. 28, 1922.,

'in my Prior Patent No. 1,132,163.

STATES F F l C E t EDGAR M. CLARK, 0F NEW YORK, N. Y., ASSIGNOR TO STANDARD OIL COMPANY, OF NEW YORK, N. Y., A CORPORATION OF NEW JERSEY.

ART 0F PRESSURE DISTILLATION.

To all 1li/zom- I mafg/ concern.'

Be it known that I, EDGAR M. CLARK,a citizen of the nited States,'residing at New York. in the county of New York and State of New York, have invented a new and useful Improvement in the Art of Pressure Distillation, of which the following is a specification.

The present invention relates to the art of pressure distillation of petroleum oils and will be fully understood from the following specification, taken in connection with the accompanying drawing, which shows in diagrammatic plan view (partially broken away) apparatus suitable for carrying out this invention.

The present invention contemplates the use of an apparatus of the type illustrated in diagrammatic plan on the drawing. In brief, this apparatus consists of a battery of pressure stills connected with an adequate number of tar stills of the continuous type, and means for feeding the distillate from the tai-.stills back to the pressure stills. The general method of operation with this equipment is as follows:

The pressure stills are charged'with a heavy petroleum distillate. such as gas oil, and are brought into operation and operated generally according to the manner described Some short time after normal ruiming conditions are established, fresh stock is fed into the stills and simultaneouslyv tar is withdrawn therefrom and delivered continuously to one or more tar stills in which it is redistilled partly or wholly by its residual heat. The distillate from the tar. being free from suspended carbon and dirt. is continuously returned to the pressure stills. By this method of operation a process, which as heretofore commonly practiced was of a batch or intermittent nature. becomes substantially continuous in character with a resulting increased output of the equipment and reduced fuel and labor costs.

The manner in which this general plan of operation is carried out according to my invention will now be described with reference to the apparatus illustrated by the drawings. in whiche- Figure 1 is a plan View. somewhat dlagrammatic, showing t-he apparatus; Figure 2 is a sectional elevation on the line 2 2 of Figure 1.

Specication of Letters Patent. Patemttgd Rian', 28, 1922,

Application filed April 21, 1919.

serial No. 291,503.

stills arranged in a row as indicated by the Y drawing and be at the same horizontal level. Each still will be equipped with its individual reflux fractionating condenser which may, for example, be of the type illustrated in my co-pending application, Serial No. 286,263, executed by me on the 26th day of March, 1919. From these condensers, which are designated 11 in the drawing, the vapor line 12 of each still leads to a water-cooled condenser 13 and thence to a receiving drum for distillate, designated 14.-. The distillate as collected in this receiving drum may be drawn out by the distillate lines 15 of which there will generally' be two as indicated by the drawing. The top of each` receiving drum will be connected by branching Valved pipes designated, 16 and 1T, to low and highpressure gas mains designated 18 and 19 respectively. A cross-over connection 20 between these gas mains is equipped with a p1essu're-regulating valve 21. The construction of this part of the apparatus is more fully described and illustrated in my former patent heretofore referred to.

At a point below the normal liquid level in each still, the particular point being determined by the form of still employed, there will be connected a valved high-pressure tar draw-off as indicated at 22 on the drawing. These tar draw-off lines from the several stills will be manifolded to a common highpressure tar header 23. At the end of the battery this high-pressure tar header will -discharge into a low-pressure tar line 24 through a pressure release and control valve 25. A separate low-pressure tar header designated 26 will also extend along the battery and be provided with valve connections 2T for each still, these low-pressure. tar connections being tapped into the lowest point in the still, so that the latter may be completely `emptied through them. The lowpressure tar header 26 will communicate with t-he tar line 2l through a valve connection 28. y

T he tar line 24 discharges into a continuous tar still 29 arranged preferably at the same horizontal level as the still battery. 'here, as will often be the case, the number of pressure stills in the battery is so large as to require the use of more than one tar still, I prefer to employ two or more tar stills arranged for continuous operation. Thus, as is shown in the drawing, there is a second tar still 30 beyond the still 29, the second still being connected with the first by an overflow connection 3l of the usual type. From the tar still 3() a line 32 will be carried off' through the usual tar coolers and to storage. There may be employed a crossover connection 33 from the low-pressure tar header 26 to the line 32.

Each tar still will be equipped with its separate condenser 34 and receiver 35. From the receivers distillate lines 36, which may be manifolded, lead to atar distillate pump 37 which discharges by the line 38 into the feed-stock tank 39. Into the latter there is connected a feed line 40 through a pressure feed pump 41. The feed line will have valved connections. such as those shown at 42. discharging into eac-h still of the battery. Preferably these feed connections will feed the stills through the reflux condensers 11 thereof. as is described in my co-pending application heretofore referred to.

The normal condition of operation in a battery pressure-still. such as that described, will be as follows:

Each still will Icontain a charge of relatively heavy petroleum oil. such as gas oil, and the stills will all be in communication through their vapor pipes. condensers and receiving drums with the same high-pressure gas main 19.4 The pressure in this main will be continuously controlled by the regulating valve 21 through which the high-pressure gas escapes to the low-pressure main 18. The operating pressure of the high-pressure main may be. for example. ninety pounds per square inch. Each still will be fired separately at lauch a rate as to keep its contents at a temperature of about 7400 F.. under which conditions decomposition of the oil within the still will proceed at a relatively rapid rate, and the evolved vapors of the lighter products of the decomposition admixed to a considerable extent with the heavier products will pass from the stills into the reflux fractionating condensers 11. In the latter. a separation of the heavier and lighter constituents of the vapors will take place. the heavier constituents heilig continuously returned to the still. while the lighter ones pass unchanged to the watercooled condensers 13 and thence to the receiving drums 14. Those portions of the lighter products of the operation which are condensable under the temperature and pressure conditions obtainin will be withdrawn as liquid from the receivmg drums, while the incondensable fractions, that is, the Fixed gases. will be discharged continuously from the tops of the receiving drums through the open pipe connections 17 to the high-pressure gas main 19.

By virtue of this open communication between all of the stills 0f the battery afforded by the high-pressure gas main, the entire battery will operate under the same pressure, any variations of pressure incident to irregular operation affecting the entire battery in the same way and at the same time.

Assuming that the battery pressure-still is operating in the normal fashion as described above, the feed-pump 11 will be set in operation and the valves in the feed connections to the individual stills will be opened to such an extent as to supply fresh stock to each still at a rate somewhat greater than the production of distillate within the still. For example, if the stills are producing distillate at the rate of 250 gallons per hour (for each still having a charging capacity of 13,000 gallons), the fresh charge of heavy oil may be continuously fed in at the rate of 60 gallons per hour. Simultaneously all of the stills in the battery will be connected with the high-pressure tar header 23 by opening the individual valves 22. The pressure release and control valve 25 will now be open and regulated so as to maintain the liquid level at the desired point within the stills. Since each still is being fed 210 gallons more per hour than it is producing as distillate. this amount of tar will therefore flow continuously from each still into the tar header 23. Since all of the stills are operating under precisely the same pressure at all times. and since they are all located on the same level, the liquid level within all of the stills will remain the same. the level for the 'entire battery being controlled by the setting of the valve 25.

The tar released from the valve 25 into the tar line 21 will be fed continuously to the first tar` Istill 29. In the latter, its residual or super heat (the tar still operating at atmospheric pressure) will be suflicient to vaporize a considerable percentage of its volume. the vapors being collected as distilled in the receiver 35. lf' desired, the Still 29 may be operated entirely by residual or super heat in this manner, no additional heat being applied to it. From the still 29 the tar (which may be reduced in volume to a considerable extent) may overow into the still 30 which will be fired to effect a further reduction in volume and production of distillate. For example. the tar received from the pressure stills and fed by the tar stills may have a gravity of 27 Baumel and by the tar stills this tar may be reduced to 11 Baume, which is accomplished by taking off yapproximately 55 per cent of its volume as distillate. I prefer to aid the distillation in both tar stills by the use of submerged steam jets therein, the distillation with steam givlng a better product, particularly a better be evacuated through the low-pressure tar ramper residual product. The mixed distillate takenv olf the two tar stills may have a gravity of 31.5o Baum. These mixed distillates through the manifold connections shown and 5 by the pump 37 will be continuously -delivered to the feed tank 39 in which they will operation of any particular still in the battery," the vlatter is disconnected from theA high-pressure header 19 by shutting olf the valve in the `connection 17.- Simultaneously, the connection 22 to the high-pressure tar line will be closed and the feed to that still stopped. The contents of the still may then vline 26 which may discharge into the tar line 24 and thence to the tar re-running stills or by the cross-over 33 directly into the residual line from the tar stills.

l have found that by continuously withdrawing a portion of the material under treatment from the pressure-stills and continuously feeding a suicient quantity ol fresh stock to maintain a constant level therein, it ispossible to prolong the continuous period of operation of the stills to such an extent that the output of light distillate `:from the equipment is substantially in; creased. l prefer to operate by charging each still into the battery initially and running`od by the batch method, that is, without either feeding or withdrawing tar, ap-

proximately twenty per cent of the contents of the stil-l before putting the still into communication with the high-pressurtar header and beginningl the feed. l have found it easily possible to operate mills in this manner continuously for aweek at a time withthe pressure process `for the out interrupting purpose of cleaning the stills.

While l have in the foregoing described in considerable detail the preferred process according to my invention, together with a lay-out of ap aratus suitable for this particular process, it w-ill be understood that.

'this is" illustrative only, and that my invention is-not limited to the details of procedure or apparatus described, except in so far as such limitations form a 'part of the accompanying claims', in which it is my intention to claim. all novelty inherent in the invention as broadly as is permissible in view of the prior' art.

What l claim is- 1. .The improvement in the art of pressure distillation of petroleum oils for the purpose of producing lighter products by pyrogenesis, which consists in maintaining a considerable body of said oily under cracking conditions of temperature and pressure, continuously withdrawing oil from the said body, releasing the pressure from the withdrawn oil while the latter is in a heated condition whereby its lighter fractions will distill o collecting such lighter fractions and returning them to the oilbody for further cracking therein.

2. 'll-he improvement in the art of pres-l sure dimillation of petroleum oil which consists 1n carrying on the distilling operation slmultaneously in aplurality Vof separate stills, all at substantially the same horizontal level, maintaining free' communication between the vapor spaces of all of said stills,

maintaining separate free communication between the liquid bodies of alll of saidl stills, withdrawing liquid .from .the communication means, whereby liquidis withdrawnffrom all stills, and simultaneously feedin said stills separately and independent y.

' 3. A continuous process of distilling petroleum oil under pressure Iwhich consists in' operating simultaneously a pluralty of separate pressure stills, all at the same horizontal level, separately condensing and collectthe l ing the distillate of each still, maintaining y a unifonn'pressure in all of the stills b permitting a free inter-dow. of u'ncon ensed products of distillation between stills, withdrawing liquid from all stills simultaneously .and .through a common draw-0E line, distilling the withdrawn liquid, and feedin the'stlls separately with the distillate o `the withdrawn liquid supplemented by a sinhcient quantity of fresh oil to maintain a constant level in each still.

l. The distillatory apparatus comprising lill@ a plurality of stills, vapor apparatus con- Y nected to each of said stills, each vapor apparatus oomprisinga condenser system, a

`gas main communicating with the vamr apratas of each still, a tar line communicating with each mill, a tar still into which the tar line discharges, means for feeding mech into the vapor apparatus of each still, and means connectin the condenser ot said tar Stm m Said dmhlsa n eraan lllb , DISOLAlMEFz.' Y f 1,4lO,797.-Edgar M. Clark, NewV York, N. Y. ART 0F PRESSURE DIsTILLATIoN.

Patent dated March 28, 1922. Disclaimer filed November 19, 1925, by the assignee by mesne assignments, Standard Development Company.

Hereby enters this disclaimer to tha-tpart of the olaim n Asaid specification which is' in the following Words, to wit: i

1. Ther impro/vement in the art of pressure distillation of ypetrolewn/l oils for the purpose of producing lighter products by pyrogeneeie, which consists in maintaining `aofmriderable body of said oil under cracking conditions of temperature and pressure, continuously withdrawing oil from the said body, releasing the pressure from the withdrawn oil while the latter is in a heated condition, whereby its lighter fractions will distill of, collecting sach lighter fractions and returning them to the oil body for further cracking therein. l

[Oficial Gazette December v15, 1925.] 

